Accepted Answer

Probably you should have your property result named as the field returned by the SP (value) but this creates a conflict with a reserved keyword

So, change the SP to rename the field returned as the property of your model

CREATE PROCEDURE [dbo].[P_GetStringConfig](
@iCode CHAR(20))
AS
BEGIN
SET NOCOUNT ON
SELECT Value AS result
FROM T_SReq_Config WITH (NOLOCK)
WHERE Code = @iCode
IF @@ERROR <> 0
RETURN @@ERROR
RETURN 0
END

Also, I suggest to change the code to use FirstOrDefault in case your SP doesn't find anything your code will raise an Exception